REMARKS ON THE CONTEXT OF HELMHOLTZ’S “UEBER DAS WESEN DER FÄULNISS UND GÄHRUNG”

Numerous scientific fields felt the impact of Hermann von Helmholtz’s (1821–1894) wide-ranging interests and talents. A cursory survey of the major accomplishments in his scientific career shows the astonishing range of his investigations. The research on putrefaction and fermentation is an example of his early research and represents a topic to which he devoted little attention in his later career. It clearly has some significance for Helmholtz’s development as a scientist. The research is an early chapter in the evolution of his place in the debate then unfolding regarding the boundaries of chemistry and physiology as well as the proper application of the physical and chemical sciences to the study of life. Before undertaking this work in 1842, Helmholtz had been a medical student at the Königliches medicinisch-chirurgisches Friedrich-Wilhelms-Institut, in Berlin. From 1838 till 1842, he attended a range of courses, among them lectures by Eilhard Mitscherlich, Gustav Magnus, and Johannes Müller. Helmholtz carried out research under the guidance of Müller on the structure of nerve ganglion cells that he completed in 1842. The work was published as a dissertation entitled: “De fabrica systematis nervosi evertebratorum.” Soon after he turned to the research on putrefaction and fermentation, which was published in 1843. He then began to pursue an extended research project on animal heat, investigating the heat generated and the transformation of matter in the contraction of frog muscles. This work continued through 1848 and was importantly related to his thinking on the interaction of forces leading to the famous paper in 1847, Ueber die Erhaltung der Kraft. In the late 1840s and early 1850s he carried out experiments to determine the velocity of the nerve impulse. In this work he not only determined the speed of the impulse (quite slow relative to some prior opinions), but also developed a set of experimental skills that would serve him well in his ambitious and synthetic research projects in physiological optics, physiological acoustics, electrodynamics, and thermodynamics (among others).